The field of the present invention is catalytic filters. More specifically, the present invention is directed to a polymeric microporous matrix to which a biologically active agent such as an enzyme or an antibody is applied to perform the catalysis as reactive materials come in contact with the matrix either by bulk flow or by diffusion.
The polymeric microporous matrix will sometimes be referred to herein as a microporous membrane filter, since such materials have found wide usage for filtration.
It is well known that enzymes can function as catalysts for certain biochemical reactions. However, the recovery of enzymes from solutions into which they have been introduced to act as a catalyst is often complex and difficult. A further problem associated with the use of enzymes as catalysts is that enzymes have a relatively short shelf life. This short shelf life is significant because enzymes are often extremely expensive and difficult to obtain, particularly in high purity.
It is known that the recovery problem is significantly reduced if the enzyme is bound to the surface of an insoluble substance. With an enzyme bound to such a surface, the solution containing the reactants for which the enzyme is a catalyst is then passed over the surface to which the enzyme is bound to allow the enzyme to catalyse a reaction. Since the enzyme is bound, with this procedure, it remains in place and its recovery from the reactive solution is not required.
One known method for binding an enzyme to a surface is to use a film-like non-porous carrier which is capable of complexing and binding to enzymes so that enzymatic reactions can be effected by passing reactants over the membrane or film. In this known prior art procedure, enzymes are bound to or immobilized on a thin protein membrane formed of a protein such as collagen or zein. The particular enzyme is bound to the membrane after the membrane is swollen with a weak acid. The foregoing procedure for catalysing reactions with bound enzymes has a number of deficiencies, the most significant of which is that with such non-porous films the amount of catalyst which can be bound per unit volume is low as compared with the amount which can be bound per unit volume with the structure of the present invention. Thus much more of the prior non-porous structure is required to obtain a given catalytic capacity.